Kaikoura quake 'wake up call' for Wellington

Police and fire service staff secure the area around the Reading Cinema car park building in Wellington after the Kaikoura earthquake. Photo / File

A massive quake in the country's capital could cost the country almost $29 billion a new report states, creating a "catastrophic impact" on the city.

Analysts modelled the figure on a quake the size that rocked Christchurch in February 2011 that killed 185 people.

Deloitte's The Forgotten Impact report focuses on the effects of the Kaikoura earthquake on those living in the capital, how resilient residents are, what if it had been worse and what the response should be as a country.

"The lasting economic impact created by the Kaikoura earthquake in Wellington is a wake-up call.

"It goes without saying that a similar size earthquake occurring directly under Wellington city would have a catastrophic impact on Wellington and, as Wellington's economy is second only to Auckland in size, the country more generally."

Although the overall cost to the country is estimated at $29b, $26b of that would affect Wellington itself.

The report is similar to one released by GNS to the Herald in 2014 in which it determined an 8.9 earthquake and tsunami in the Hikurangi subduction zone could kill 40 people because of earthquake shaking - but a further 3200 in a tsunami that followed.

Although scientists were uncertain whether a rupture could extend from the subduction zone to the Cook Strait, which could send tsunami waves 5m to 10m high barrelling towards both sides of the strait.

In Deloitte's report, it states that although many living and working in Wellington largely returned to normal in a few days after November's quake, there had been a "significant overhang".

"We estimate that there is a $1.25 million hit on regional GDP for every week Wellingtonians are working away from their primary office space - re-housed somewhere across the city.

"For every week that passes, the economic impact grows. Twenty-five weeks have now passed, so the total impact of this alone is at least $20m-$30m. Even so, our estimate is likely to under-state the productivity impact on GDP, as there are many businesses who have understandably chosen not to publicise the disruption to their operations," the report states.

But Finance Minister Steven Joyce told Fairfax the country could afford the bill to rebuild.

"Our experience with the Christchurch earthquakes, and the global financial crisis, shows that New Zealand has the capacity to respond.

"Most New Zealanders will realise that we will get another big event in the near future, and we need to have the capacity to borrow and rebuild."

He said the Government could afford a $29b invoice to fix Wellington, provided "we maintain a strong economy which generates a fiscal surplus, and that we use that surplus to pay down debt so we have the capacity to borrow".

"Geologically we are a young country, and we are exposed to not just earthquakes, but tsunamis and volcanoes, and we are a small country that can be exposed to other international risks. We need to have the capacity to borrow and rebuild," he told Fairfax.